Coating and heat treating apparatus



Sept. 15, 1931. A. o. AUSTIN COATING AND HEAT TREATING APPARATUS Filed Feb. 12, 1925 IN VENT OR A TTORNE YS ilk Patented Sept. 15, 1931 KINETED STATES PATENT @FFICE p ARTHUR O. AUSTIN, 0F BARBERTON, CHIS, ASSIGNOR BY M'ESNE ASSIGNMENTS, TO THE OHIO BRASS COIVII'ANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY COATING AND HEAT TREATIN G APPARATUS Application filed February 12, 1925. Serial No. 8,826.

This invention relates to the treatment of metal articles subsequent to the coating thereof for the purpose of removing excess coating material and heat treating the art1 cles. The object of the invention is to provide mechanism in which the excess material will be removed from the internal parts such as threaded openings and in which the heat treatment may be carried out without injury to the articles. Other objects will appear hereinafter.

The invention is exemplified in the combination and arrangement of the parts shown in the accompanying drawings and described in the following specification and it is more particularly pointed out in the appended claims.

In the drawings,

Fig. 1 is an elevation with parts in section showing one form of apparatus for practicing the present invention.

Fig. 2 shows a modified form of apparatus.

Fig. 3 is a top plan view with parts in section showing the apparatus in Fig. 2. In galvanizing and tinning metal parts, particularly threaded nuts, great difiiculty is found in providing a coatingon the thread which will be sufficiently uniform to permit tightening onto the bolts or other parts. The present invention deals with an improved method for eliminating this difliculty. In general, the method consists in cansing the galvanized or tinned part to traverse the path which will cause the excess zinc or tin to be thrown off without lodging on any part. The ordinary centrifugal separator is entirely unsatisfactory for the galvanizing of internally threaded parts, as some of the parts are likely to be so located in the mass that zinc or tin cannot be drained properly regardless of the amount of force applied. The present method also has the advantage thatit is continuous as it is not necessary to handle dipping baskets or other equipment. In addition, uniformityof treatment for all parts is insured which is not possible when handled in a large mass.

In Fig. 1, a rotating pot 10 attached to a spindle 11, and driven by a motor or other suitable means 12, is provided for receiving the articles which are dropped while still hot from a coating bath into a hopper 13, their path being down through the connecting tube 14. If the articles to be freed of excess coating material are dropped into the hopper in large bunches, the fall may be broken up by strikingpins 15 so that they will enter the chamber 16 without clogging. As the pot 10 with the lifting cover 17 is rotating, any article dropping down through the tube 14 will slide around and gradually acquire motion. The centrifugal force aided by the slip in the tangential direction while acquiring motion will cause the articles 18 to slide up along the side of the chamber.

The excess material thrown off will be discharged through the slot' 19. By regulating the distance between the adjacent faces of the cover 17 and the inside of the pot 10, it will be possible to insure objects having a flat side, such as nuts, to assume a position with the flat side against the inner wall of the pot so that the tapped holes will extend radially of the pot and therefore'be drained by centrifugal action. In general, howeveiyowing to the sliding action before acquiring thevelocity of the pot, they will assume the proper position. This sliding action upon entering is very beneficial as it tends to throw off excess material so that it will not again accumulate on the piece.

The sliding action also insures the pot being kept free from excess material and in a work- I ing condition so that it is suitable for continuous operation. lVhere the objects are small or the flow of material is not suflicient to keep the chamber heated properly, or where it is desirable to increase the temperature during the operation, heat may be applied by a gas burner 20 which discharges down through the tube 14. The centrifugal force draws heated air or flame down through the pot. where very high temperatures are used, the burner 20 may be utilized to produce a neutral or reducing atmosphere so as to prevent serious oxidization of the surface. The heating operation is very essential where it is desired to heat treat the pins 21.

parts during the process as close control of the temperature must be maintained. The cover 17 fits loosely on the tube 14. It is held in position, however, and driven by The cover 17 is provided with a collar or yoke 22 working freely in same. This collar or yoke is attached by links 22 to a movable block 23 operated by an arm 24 so that the cover may be raised to open the slot 19 and allow the articles to discharge. In many cases, it is not necessary to hold the articles in the pot as all of the material will be thrown off as they slide through and out. In discharging, it is necessary in many cases that the articles do not strike and become damaged. This may be accomplished by allowing a considerable distance around the machine so that the articles in taking their normal path will strike directly in water without previously striking any other object. In this class of machine, this is readily accomplished as the hopper may he placed above the floor and the discharge slot below the floor. Where 5 space is limited, the articles may be picked up and deflected by a shield 25 which will direct them into a water or quenching medium 26. In some cases, it may be advisable to allow the articles to strike a baf le or projection 26 which tends to knock off any excess material. This also breaks the fall and allows the articles to drop into the quenching bath.

\Vith this invention it is not necessary to 'retap the nuts or articles having blind holes which may be given a proper bath to permit draining. The threaded parts such as bolts and other objects may be handled with ease. hen threaded bolts are handled, the discharge must be made at low speed or it must be allowed to strike directly on the surface of the quenching bath or their direction gradually changed by the deflecting shield 25 so that the threads will not, be deformed.

Fig. 2 shows another form of the invention where the lever 24 is eliminated for opening the slot 19. In this case, the cover is provided with slots shown in Fig. 3, upon which the pins 21 work. The lower end of the cover is provided with cams 27. If the pot 10 is rotating in a clockwise direction looking down at the same, the driving pins 21 will be at the for-ward end of the slot 28 in which the pins work. If, however, the clutch 29 is moved upward from the driving face 30 and brought in contact with the braking face 31 by the lifting of the clutch 29 through the yoke 32 operated by the lever J 33 the speed of rotation of the pot 10 will he slackened. It is understood that the clutch 29 is free to move up and down on the shaft of spindle 11, but is provided with engaging means 34; to, rotate the spindle, and 5 pot. It will be seen that as the driving is relieved and the brake applied, the pot will be slowed down. The inertia of the cover 17 will tend to cause it to continue to rotate at the same speed at which it was rotating before the application of the brake. This will drive it forward in reference to the pot. As it drives forward, however, the lower surfaces of the cams 27 will engage the shoulder on the driving pins 21, causing the cover to lift and the discharge slot 19 to open. The same result may be accomplished by changing the speed rapidly by and means such as reversing the phase rotation of the current supply to an induction motor drive. After the slot has been opened and the articles allowed to discharge, the pot may again be speeded up by disengaging the brake and throwing the clutch into the driving face. The inertia of the cover will tend to retard it so that the pet will rotate relative to the cover and permit the cover to resume its original position with the narrow slot. The cam may be so made that the cover cannot be lifted except through a change in rotation or the arrangement may be such that suiiici-ent material breaking up will cause the cover to lift automatically. The cam 36 prevent-s discharge except through relative rotation of the cover and the pot. If, however, this; cam is removed it is seen that the cover may be forced upward by the pressure from below. The angle of the pot and cover may also be utilized to advantage, depending uponthe conditions desired. It is seen that this method or device provides for close control of the surface coating, the absence of trapping the material by irregular surfaces, and provides heat treatment for the coatingof delicate parts. The method eliminates the use of baskets and the difliculties attendant therewith. The method may be used to, prevent any cooling action and as the treatment of all articles may he identica l, the method is particularly applicable for work carried on at high tem Jeratures, or wnere close control of the quenching temverature is desired such that even though he articles may be chilled in going in, the temperature may be restored before discharging so that excess material may be driven off. By control of the conditions of the, air or gases entering the chamber not only is it possible to maintain a uniform temperature regardless of the rate of the material going through, but it is also possible to set up reducing of oxidizing conditions on the surface of the coating.

In some cases, a slight oxidation of the surface prevents the surface picking up small particles thrown off from other objects. While in other operations, particularly at high temperatures an oxidizing condition may burn off the coating. lVhere the control of the surrounding gases is iii) maintained, it is possible to use coating materials which may not be otherwise possible to use.

I claim 1. The method of removing excess coating material from articles having substantially fiat faces with openings normal to said faces wherein said articles are deposited in a receptacle having upwardly and outwardly directed side walls, the receptacle being rotated while the articles are free to slide upon said walls and to assume a position with said faces disposed against said walls.

2. The method of removing excess coating material from internally threaded articles comprising the steps of depositing said articles in a receptacle having upwardly and outwardly directed side walls, rotating said receptacle and thus causing said articles to assume a position wherein said threaded openings are arranged radially relative to the axis of rotation of said receptacle.

3. The method of removing. excess coating material from coated articles comprising the steps of feeding the articles to the central portion of a receptacle having upwardly and outwardlydirected walls, rotatin g the receptacle and thus arranging the individual articles in predetermined relation to the axis of rotation of said receptacle and causing said articles to move upwardly along said walls and. to be discharged over the top thereof.

4-. The method of removing excess coating material comprising the steps of feeding internally threaded articles having flatofaces normal to the axes of the threaded openings in said articles to the central portion of a receptacle having upwardly and outwardly directed walls, rotating the receptacle and thus causing said articles to slide upon the inner surface thereof while assuming the speed of rotation of said receptacle and to assume positions with their fiat faces toward said side wall and thereafter to climb upwardly by centrifugal action until discharged over the top of said receptacle.

5. The method of removing excess coating material from metal articles and at the same time treating said articles wherein said articles are fed to a rotating receptacle and discharged from the top of said receptacle by centrifugal action, the articles in said receptacle being subjected to heated products of combustion to facilitate escape of coating material and heat treat the articles.

6. The method of treating metal articles wherein said articles are coated and thereafter fed to the central portion of a rotating receptacle, the articles being free to slide against the walls of said receptacle and to assume a position against the faces of said walls determined by the shape of said arti cles, the centrifugal action of said receptacle operating to discharge the articles over the top'thereof into a cooling medium,the articles being subjected to heated products of combustion while in said receptacle.

7. A centrifugal device for removing excess coating material from coated articles;

of by centrifugal action, a receiver spaced outwardly from said receptacle in position to receive said art1cles as they are discharged from said receptacle, and a quenching liquid contained in said receiver into which the discharged articles fall and by which the coating thereon is cooled.

8. Apparatus for removing excess material from coated articles comprising a pot having an upwardly and outwardly inclined inner surface, means for rotating said pot, means for feeding articles to the central portion of said pot, and means within said pot for assisting positioning of said articles in predetermined relation to the axis and inner surface of said pot.

9. Apparatus for removing excess material from coated articles comprising a pot having an upwardly and outwardly inclined inner surface, means for rotating said pot, means for feeding articles to the central portion of said pot, and means projecting into the interior of said pot and having a surface spaced inwardly from the inner surface of said pot to assist in positioning articles against the inner surface of said pot.

10. Apparatus for removing excess coating material from coated articles comprising a rotary pot having an upwardly and outwardly inclined inner surface, a cover projecting into the interior of said pot and spaced inwardly from said surface a distance approximately equal to one dimension of the articles to be treated, and means for discharging material through the 'central portion of said cover into said pot.

11,. The process of treating metal articles comprising the steps of dipping the articles in a molten coating metal, depositing the coated articles in a centrifugal receptacle having imperforate side walls and cover but having an opening adjacent the top of the side walls for the escape of detached coating material, rotating the receptacle to remove excess coating metal from said articles by centrifugal action and directing a non-oxidizing heating flame into said receptacle to maintain the coating metal at a molten temperature and to prevent oxidation of said metal.

12. A centrifugal device comprising a receptacle having upwardly and outwardly directed side walls, a lid for said receptacle, means for rotating said receptacle to cause articles therein to travel upwardly along said side walls, and means for periodically lifting said lid to permit the escape of articles from the top of said receptacle said lifting means being operable during rotation of said receptacle.

In testimony whereof I have signed my name to this specification on this 7th day of February, A. D. 1925.

ARTHUR O. AUSTIN. 

